From: José Fonseca Date: Tue, 5 Jan 2010 20:41:29 +0000 (+0000) Subject: pipebuffer: Multi-threading fixes for fencing. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5b64d94390e4805e1634f0c8b5e3156e12b8b872;p=mesa.git pipebuffer: Multi-threading fixes for fencing. I had this patch on my hard drive for long time. It doesn't fully address SVGA multi-threading issues, but causes no regressions, so decided to commit while it still applies cleanly. Attention: merging this into master will cause issues due to recent changes in reference counting to fix strict aliasing rules violation. --- diff --git a/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c b/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c index 2ef4293d4d7..1ee2bf9b7c5 100644 --- a/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c +++ b/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c @@ -80,11 +80,27 @@ struct fenced_buffer_list */ struct fenced_buffer { + /* + * Immutable members. + */ + struct pb_buffer base; - struct pb_buffer *buffer; + struct fenced_buffer_list *list; + + /** + * Protected by fenced_buffer_list::mutex + */ + struct list_head head; - /* FIXME: protect access with mutex */ + /** + * Following members are mutable and protected by this mutex. + * + * You may lock this mutex alone, or lock it with fenced_buffer_list::mutex + * held, but in order to prevent deadlocks you must never lock + * fenced_buffer_list::mutex with this mutex held. + */ + pipe_mutex mutex; /** * A bitmask of PIPE_BUFFER_USAGE_CPU/GPU_READ/WRITE describing the current @@ -96,9 +112,6 @@ struct fenced_buffer struct pb_validate *vl; unsigned validation_flags; struct pipe_fence_handle *fence; - - struct list_head head; - struct fenced_buffer_list *list; }; @@ -110,15 +123,24 @@ fenced_buffer(struct pb_buffer *buf) } +/** + * Add the buffer to the fenced list. + * + * fenced_buffer_list::mutex and fenced_buffer::mutex must be held, in this + * order, before calling this function. + * + * Reference count should be incremented before calling this function. + */ static INLINE void -_fenced_buffer_add(struct fenced_buffer *fenced_buf) +fenced_buffer_add_locked(struct fenced_buffer_list *fenced_list, + struct fenced_buffer *fenced_buf) { - struct fenced_buffer_list *fenced_list = fenced_buf->list; - assert(pipe_is_referenced(&fenced_buf->base.base.reference)); assert(fenced_buf->flags & PIPE_BUFFER_USAGE_GPU_READ_WRITE); assert(fenced_buf->fence); + /* TODO: Move the reference count increment here */ + #ifdef DEBUG LIST_DEL(&fenced_buf->head); assert(fenced_list->numUnfenced); @@ -130,32 +152,16 @@ _fenced_buffer_add(struct fenced_buffer *fenced_buf) /** - * Actually destroy the buffer. + * Remove the buffer from the fenced list. + * + * fenced_buffer_list::mutex and fenced_buffer::mutex must be held, in this + * order before calling this function. + * + * Reference count should be decremented after calling this function. */ static INLINE void -_fenced_buffer_destroy(struct fenced_buffer *fenced_buf) -{ - struct fenced_buffer_list *fenced_list = fenced_buf->list; - - assert(!pipe_is_referenced(&fenced_buf->base.base.reference)); - assert(!fenced_buf->fence); -#ifdef DEBUG - assert(fenced_buf->head.prev); - assert(fenced_buf->head.next); - LIST_DEL(&fenced_buf->head); - assert(fenced_list->numUnfenced); - --fenced_list->numUnfenced; -#else - (void)fenced_list; -#endif - pb_reference(&fenced_buf->buffer, NULL); - FREE(fenced_buf); -} - - -static INLINE void -_fenced_buffer_remove(struct fenced_buffer_list *fenced_list, - struct fenced_buffer *fenced_buf) +fenced_buffer_remove_locked(struct fenced_buffer_list *fenced_list, + struct fenced_buffer *fenced_buf) { struct pb_fence_ops *ops = fenced_list->ops; @@ -177,37 +183,56 @@ _fenced_buffer_remove(struct fenced_buffer_list *fenced_list, ++fenced_list->numUnfenced; #endif - /** - * FIXME!!! - */ - - if(!pipe_is_referenced(&fenced_buf->base.base.reference)) - _fenced_buffer_destroy(fenced_buf); + /* TODO: Move the reference count decrement and destruction here */ } +/** + * Wait for the fence to expire, and remove it from the fenced list. + * + * fenced_buffer::mutex must be held. fenced_buffer_list::mutex must not be + * held -- it will be acquired internally. + */ static INLINE enum pipe_error -_fenced_buffer_finish(struct fenced_buffer *fenced_buf) +fenced_buffer_finish_locked(struct fenced_buffer_list *fenced_list, + struct fenced_buffer *fenced_buf) { - struct fenced_buffer_list *fenced_list = fenced_buf->list; struct pb_fence_ops *ops = fenced_list->ops; + enum pipe_error ret = PIPE_ERROR; #if 0 debug_warning("waiting for GPU"); #endif + assert(pipe_is_referenced(&fenced_buf->base.base.reference)); assert(fenced_buf->fence); + + /* + * Acquire the global lock. Must release buffer mutex first to preserve + * lock order. + */ + pipe_mutex_unlock(fenced_buf->mutex); + pipe_mutex_lock(fenced_list->mutex); + pipe_mutex_lock(fenced_buf->mutex); + if(fenced_buf->fence) { - if(ops->fence_finish(ops, fenced_buf->fence, 0) != 0) { - return PIPE_ERROR; + if(ops->fence_finish(ops, fenced_buf->fence, 0) == 0) { + /* Remove from the fenced list */ + /* TODO: remove consequents */ + fenced_buffer_remove_locked(fenced_list, fenced_buf); + + p_atomic_dec(&fenced_buf->base.base.reference.count); + assert(pipe_is_referenced(&fenced_buf->base.base.reference)); + + fenced_buf->flags &= ~PIPE_BUFFER_USAGE_GPU_READ_WRITE; + + ret = PIPE_OK; } - /* Remove from the fenced list */ - /* TODO: remove consequents */ - _fenced_buffer_remove(fenced_list, fenced_buf); } - fenced_buf->flags &= ~PIPE_BUFFER_USAGE_GPU_READ_WRITE; - return PIPE_OK; + pipe_mutex_unlock(fenced_list->mutex); + + return ret; } @@ -215,8 +240,8 @@ _fenced_buffer_finish(struct fenced_buffer *fenced_buf) * Free as many fenced buffers from the list head as possible. */ static void -_fenced_buffer_list_check_free(struct fenced_buffer_list *fenced_list, - int wait) +fenced_buffer_list_check_free_locked(struct fenced_buffer_list *fenced_list, + int wait) { struct pb_fence_ops *ops = fenced_list->ops; struct list_head *curr, *next; @@ -228,21 +253,28 @@ _fenced_buffer_list_check_free(struct fenced_buffer_list *fenced_list, while(curr != &fenced_list->delayed) { fenced_buf = LIST_ENTRY(struct fenced_buffer, curr, head); + pipe_mutex_lock(fenced_buf->mutex); + if(fenced_buf->fence != prev_fence) { int signaled; if (wait) signaled = ops->fence_finish(ops, fenced_buf->fence, 0); else signaled = ops->fence_signalled(ops, fenced_buf->fence, 0); - if (signaled != 0) + if (signaled != 0) { + pipe_mutex_unlock(fenced_buf->mutex); break; + } prev_fence = fenced_buf->fence; } else { assert(ops->fence_signalled(ops, fenced_buf->fence, 0) == 0); } - _fenced_buffer_remove(fenced_list, fenced_buf); + fenced_buffer_remove_locked(fenced_list, fenced_buf); + pipe_mutex_unlock(fenced_buf->mutex); + + pb_reference((struct pb_buffer **)&fenced_buf, NULL); curr = next; next = curr->next; @@ -256,30 +288,25 @@ fenced_buffer_destroy(struct pb_buffer *buf) struct fenced_buffer *fenced_buf = fenced_buffer(buf); struct fenced_buffer_list *fenced_list = fenced_buf->list; - pipe_mutex_lock(fenced_list->mutex); assert(!pipe_is_referenced(&fenced_buf->base.base.reference)); - if (fenced_buf->fence) { - struct pb_fence_ops *ops = fenced_list->ops; - if(ops->fence_signalled(ops, fenced_buf->fence, 0) == 0) { - struct list_head *curr, *prev; - curr = &fenced_buf->head; - prev = curr->prev; - do { - fenced_buf = LIST_ENTRY(struct fenced_buffer, curr, head); - assert(ops->fence_signalled(ops, fenced_buf->fence, 0) == 0); - _fenced_buffer_remove(fenced_list, fenced_buf); - curr = prev; - prev = curr->prev; - } while (curr != &fenced_list->delayed); - } - else { - /* delay destruction */ - } - } - else { - _fenced_buffer_destroy(fenced_buf); - } + assert(!fenced_buf->fence); + +#ifdef DEBUG + pipe_mutex_lock(fenced_list->mutex); + assert(fenced_buf->head.prev); + assert(fenced_buf->head.next); + LIST_DEL(&fenced_buf->head); + assert(fenced_list->numUnfenced); + --fenced_list->numUnfenced; pipe_mutex_unlock(fenced_list->mutex); +#else + (void)fenced_list; +#endif + + pb_reference(&fenced_buf->buffer, NULL); + + pipe_mutex_destroy(fenced_buf->mutex); + FREE(fenced_buf); } @@ -290,24 +317,23 @@ fenced_buffer_map(struct pb_buffer *buf, struct fenced_buffer *fenced_buf = fenced_buffer(buf); struct fenced_buffer_list *fenced_list = fenced_buf->list; struct pb_fence_ops *ops = fenced_list->ops; - void *map; + void *map = NULL; + + pipe_mutex_lock(fenced_buf->mutex); assert(!(flags & PIPE_BUFFER_USAGE_GPU_READ_WRITE)); /* Serialize writes */ if((fenced_buf->flags & PIPE_BUFFER_USAGE_GPU_WRITE) || ((fenced_buf->flags & PIPE_BUFFER_USAGE_GPU_READ) && (flags & PIPE_BUFFER_USAGE_CPU_WRITE))) { - if(flags & PIPE_BUFFER_USAGE_DONTBLOCK) { + if((flags & PIPE_BUFFER_USAGE_DONTBLOCK) && + ops->fence_signalled(ops, fenced_buf->fence, 0) == 0) { /* Don't wait for the GPU to finish writing */ - if(ops->fence_signalled(ops, fenced_buf->fence, 0) == 0) - _fenced_buffer_remove(fenced_list, fenced_buf); - else - return NULL; - } - else { - /* Wait for the GPU to finish writing */ - _fenced_buffer_finish(fenced_buf); + goto done; } + + /* Wait for the GPU to finish writing */ + fenced_buffer_finish_locked(fenced_list, fenced_buf); } #if 0 @@ -324,6 +350,9 @@ fenced_buffer_map(struct pb_buffer *buf, fenced_buf->flags |= flags & PIPE_BUFFER_USAGE_CPU_READ_WRITE; } +done: + pipe_mutex_unlock(fenced_buf->mutex); + return map; } @@ -332,6 +361,9 @@ static void fenced_buffer_unmap(struct pb_buffer *buf) { struct fenced_buffer *fenced_buf = fenced_buffer(buf); + + pipe_mutex_lock(fenced_buf->mutex); + assert(fenced_buf->mapcount); if(fenced_buf->mapcount) { pb_unmap(fenced_buf->buffer); @@ -339,6 +371,8 @@ fenced_buffer_unmap(struct pb_buffer *buf) if(!fenced_buf->mapcount) fenced_buf->flags &= ~PIPE_BUFFER_USAGE_CPU_READ_WRITE; } + + pipe_mutex_unlock(fenced_buf->mutex); } @@ -350,11 +384,14 @@ fenced_buffer_validate(struct pb_buffer *buf, struct fenced_buffer *fenced_buf = fenced_buffer(buf); enum pipe_error ret; + pipe_mutex_lock(fenced_buf->mutex); + if(!vl) { /* invalidate */ fenced_buf->vl = NULL; fenced_buf->validation_flags = 0; - return PIPE_OK; + ret = PIPE_OK; + goto done; } assert(flags & PIPE_BUFFER_USAGE_GPU_READ_WRITE); @@ -362,14 +399,17 @@ fenced_buffer_validate(struct pb_buffer *buf, flags &= PIPE_BUFFER_USAGE_GPU_READ_WRITE; /* Buffer cannot be validated in two different lists */ - if(fenced_buf->vl && fenced_buf->vl != vl) - return PIPE_ERROR_RETRY; + if(fenced_buf->vl && fenced_buf->vl != vl) { + ret = PIPE_ERROR_RETRY; + goto done; + } #if 0 /* Do not validate if buffer is still mapped */ if(fenced_buf->flags & PIPE_BUFFER_USAGE_CPU_READ_WRITE) { /* TODO: wait for the thread that mapped the buffer to unmap it */ - return PIPE_ERROR_RETRY; + ret = PIPE_ERROR_RETRY; + goto done; } /* Final sanity checking */ assert(!(fenced_buf->flags & PIPE_BUFFER_USAGE_CPU_READ_WRITE)); @@ -379,17 +419,21 @@ fenced_buffer_validate(struct pb_buffer *buf, if(fenced_buf->vl == vl && (fenced_buf->validation_flags & flags) == flags) { /* Nothing to do -- buffer already validated */ - return PIPE_OK; + ret = PIPE_OK; + goto done; } ret = pb_validate(fenced_buf->buffer, vl, flags); if (ret != PIPE_OK) - return ret; + goto done; fenced_buf->vl = vl; fenced_buf->validation_flags |= flags; - return PIPE_OK; +done: + pipe_mutex_unlock(fenced_buf->mutex); + + return ret; } @@ -404,29 +448,36 @@ fenced_buffer_fence(struct pb_buffer *buf, fenced_buf = fenced_buffer(buf); fenced_list = fenced_buf->list; ops = fenced_list->ops; - - if(fence == fenced_buf->fence) { - /* Nothing to do */ - return; - } - assert(fenced_buf->vl); - assert(fenced_buf->validation_flags); - pipe_mutex_lock(fenced_list->mutex); - if (fenced_buf->fence) - _fenced_buffer_remove(fenced_list, fenced_buf); - if (fence) { - ops->fence_reference(ops, &fenced_buf->fence, fence); - fenced_buf->flags |= fenced_buf->validation_flags; - _fenced_buffer_add(fenced_buf); - } - pipe_mutex_unlock(fenced_list->mutex); + pipe_mutex_lock(fenced_buf->mutex); + + assert(pipe_is_referenced(&fenced_buf->base.base.reference)); + + if(fence != fenced_buf->fence) { + assert(fenced_buf->vl); + assert(fenced_buf->validation_flags); + + if (fenced_buf->fence) { + fenced_buffer_remove_locked(fenced_list, fenced_buf); + p_atomic_dec(&fenced_buf->base.base.reference.count); + assert(pipe_is_referenced(&fenced_buf->base.base.reference)); + } + if (fence) { + ops->fence_reference(ops, &fenced_buf->fence, fence); + fenced_buf->flags |= fenced_buf->validation_flags; + p_atomic_inc(&fenced_buf->base.base.reference.count); + fenced_buffer_add_locked(fenced_list, fenced_buf); + } + + pb_fence(fenced_buf->buffer, fence); - pb_fence(fenced_buf->buffer, fence); + fenced_buf->vl = NULL; + fenced_buf->validation_flags = 0; + } - fenced_buf->vl = NULL; - fenced_buf->validation_flags = 0; + pipe_mutex_unlock(fenced_buf->mutex); + pipe_mutex_unlock(fenced_list->mutex); } @@ -436,6 +487,7 @@ fenced_buffer_get_base_buffer(struct pb_buffer *buf, pb_size *offset) { struct fenced_buffer *fenced_buf = fenced_buffer(buf); + /* NOTE: accesses immutable members only -- mutex not necessary */ pb_get_base_buffer(fenced_buf->buffer, base_buf, offset); } @@ -475,6 +527,8 @@ fenced_buffer_create(struct fenced_buffer_list *fenced_list, buf->buffer = buffer; buf->list = fenced_list; + pipe_mutex_init(buf->mutex); + #ifdef DEBUG pipe_mutex_lock(fenced_list->mutex); LIST_ADDTAIL(&buf->head, &fenced_list->unfenced); @@ -516,7 +570,7 @@ fenced_buffer_list_check_free(struct fenced_buffer_list *fenced_list, int wait) { pipe_mutex_lock(fenced_list->mutex); - _fenced_buffer_list_check_free(fenced_list, wait); + fenced_buffer_list_check_free_locked(fenced_list, wait); pipe_mutex_unlock(fenced_list->mutex); } @@ -538,11 +592,13 @@ fenced_buffer_list_dump(struct fenced_buffer_list *fenced_list) next = curr->next; while(curr != &fenced_list->unfenced) { fenced_buf = LIST_ENTRY(struct fenced_buffer, curr, head); + pipe_mutex_lock(fenced_buf->mutex); assert(!fenced_buf->fence); debug_printf("%10p %7u %7u\n", (void *) fenced_buf, fenced_buf->base.base.size, p_atomic_read(&fenced_buf->base.base.reference.count)); + pipe_mutex_unlock(fenced_buf->mutex); curr = next; next = curr->next; } @@ -552,6 +608,7 @@ fenced_buffer_list_dump(struct fenced_buffer_list *fenced_list) while(curr != &fenced_list->delayed) { int signaled; fenced_buf = LIST_ENTRY(struct fenced_buffer, curr, head); + pipe_mutex_lock(fenced_buf->mutex); signaled = ops->fence_signalled(ops, fenced_buf->fence, 0); debug_printf("%10p %7u %7u %10p %s\n", (void *) fenced_buf, @@ -559,6 +616,7 @@ fenced_buffer_list_dump(struct fenced_buffer_list *fenced_list) p_atomic_read(&fenced_buf->base.base.reference.count), (void *) fenced_buf->fence, signaled == 0 ? "y" : "n"); + pipe_mutex_unlock(fenced_buf->mutex); curr = next; next = curr->next; } @@ -579,8 +637,8 @@ fenced_buffer_list_destroy(struct fenced_buffer_list *fenced_list) #if defined(PIPE_OS_LINUX) || defined(PIPE_OS_BSD) || defined(PIPE_OS_SOLARIS) sched_yield(); #endif - _fenced_buffer_list_check_free(fenced_list, 1); pipe_mutex_lock(fenced_list->mutex); + fenced_buffer_list_check_free_locked(fenced_list, 1); } #ifdef DEBUG @@ -588,6 +646,7 @@ fenced_buffer_list_destroy(struct fenced_buffer_list *fenced_list) #endif pipe_mutex_unlock(fenced_list->mutex); + pipe_mutex_destroy(fenced_list->mutex); fenced_list->ops->destroy(fenced_list->ops);